Self-laying track-type work machines utilize an endless track chain assembly joined together by interconnected link arrangements. The link arrangements include overlapping link members which form a pair of continuous rails. A plurality of track roller assemblies bear the weight of the machine, and guide the track chain by engaging the link rails as the track chain rotates about a drive sprocket wheel and one or more idler wheels. The roller assemblies rotate from frictional engagement with the moving link rails. The continuous contact between the rails and the roller treads produces wear of the two components with resulting replacement or repair. Such replacement or repair increases the operating cost and downtime of the machine. If the useable wear life of the roller treads can be extended, the overall value and service of the machine is increased.
One method of extending the useful life of the roller treads have been proposed, which includes providing replaceable wear members for the roller tread portion. One type of track roller assembly having replaceable roller tread portions is disclosed in U.S. Pat. No. 3,910,128, issued on Oct. 7, 1975 to R. L. Boggs et al. The tread portion of this roller assembly includes an inner resilient collar and an outer metallic ring. The tread portions are held between a pair of flanges and the flanges are secured in place by threaded retaining means. This particular arrangement would appear to function satisfactorily for its intended purpose. However, this assembly contains a considerable number of parts and requires time and effort to assemble the parts together.
Another type of track roller assembly having a tread portion separate from the roller shell is disclosed in U.S. Pat. No. 3,154,958, issued Nov. 3, 1964 to W. C. Codwell et al. The separate tread portions are pressfitted to the roller shell, or hub, and are held against axial movement by split expansion rings. Two part bushings, between the roller shell and the shaft, are secured to the roller shell by a plurality of bolts which thread into the roller shell. Although this roller assembly would appear to function in a satisfactory manner, the amount of useable wear life of the tread portions is somewhat limited. Replacement of the tread portions would cause downtime of the machine.
The present invention is directed to overcoming one or more of the problems as set forth above.